Elevated temperature properties of SiC-fibre reinforced CuCr1Zr, a candidate heat sink material for application in fusion reactors

Abstract

In experimental fusion reactors the copper alloy CuCr1Zr is a widely used alloy for heat sinks. The thermal conductivity at room temperature of this alloy measures 370 W m−1K−1. Its room temperature mechanical properties with a tensile strength of 400–470 MPa and a yield stress of 280–380 MPa are based on a dispersion hardening and an aging treatment. The long-term temperature capability is however limited due to an overaging effect taking place in the temperature range of roughly 350 °C up to an aging temperature of 480 °C. A possibile way to improve the properties at elevated temperatures is by embedding stiff, strong fibres, e.g. SiC-fibres. In the present study, the mechanical behaviour of SiC-fibre reinforced CuCr1Zr is determined at 550 °C and compared with the room temperature properties. The thermal conductivity is considerably reduced by embedding SiC-fibres. From measured values of the thermal conductivity of the composite material the axial thermal conductivity of the SiC-fibre can be roughly estimated to be 16 W m−1K−1.